Hadoop 入门(二)

目录

Hadoop 安装

单点启动&集群启动

访问 HDFS

常用配置

常用命令

启动关闭集群

单节点启动&停止

namenode 单节点启动

[root@node0 name]# hadoop-daemon.sh start namenode
starting namenode, logging to /usr/local/hadoop/logs/hadoop-root-namenode-node0.out
[root@node0 name]# jps
3585 Jps
3515 NameNode

datanode 单节点启动

[root@node1 ~]# hadoop-daemon.sh start datanode
starting datanode, logging to /usr/local/hadoop/logs/hadoop-root-datanode-node1.out
[root@node1 ~]# jps
2358 DataNode
2391 Jps

namenode 单节点停止

[root@node0 name]# hadoop-daemon.sh stop namenode
stopping namenode
[root@node0 name]# jps
3616 Jps

datanode 单节点停止

[root@node1 ~]# hadoop-daemon.sh stop datanode
stopping datanode
[root@node1 ~]# jps
2465 Jps

集群启动&停止

修改配置文件

[root@node0 hadoop]# cd /usr/local/hadoop/etc/hadoop/
[root@node0 hadoop]# vi slaves

/usr/local/hadoop/etc/hadoop/slaves

node1
node2
node3

/usr/local/hadoop/etc/hadoop/slaves 文件中记录 namenode 管理的 datanode

整个集群启动

[root@node0 hadoop]# start-dfs.sh

整个集群停止

[root@node0 hadoop]# start-dfs.sh

根据提示输入 node1 node2 node3 的密码即可启动&停止

ssh 免密登录

[root@node0 .ssh]# cd /root/.ssh/
[root@node0 .ssh]# ssh-keygen -t rsa
[root@node0 .ssh]# ls
id_rsa  id_rsa.pub  known_hosts

ssh-keygen -t rsa 这个命令执行之后一路回车。

完了之后会多两个文件 id_rsa 和 id_rsa.pub。

id_rsa 是私钥 id_rsa.pub 是公钥。

需要将 id_rsa.pub 公钥复制到 node1 node2 node3 的机器上即可

[root@node0 .ssh]# ssh-copy-id node1

免密启动&停止

[root@node0 .ssh]# start-dfs.sh
Starting namenodes on [node0]
node0: starting namenode, logging to /usr/local/hadoop/logs/hadoop-root-namenode-node0.out
node2: datanode running as process 2516. Stop it first.
node1: starting datanode, logging to /usr/local/hadoop/logs/hadoop-root-datanode-node1.out
node3: ssh: connect to host node3 port 22: No route to host
Starting secondary namenodes [0.0.0.0]
0.0.0.0: starting secondarynamenode, logging to /usr/local/hadoop/logs/hadoop-root-secondarynamenode-node0.out
[root@node0 .ssh]# jps
5037 SecondaryNameNode
5149 Jps
4846 NameNode
[root@node0 .ssh]# stop-dfs.sh
Stopping namenodes on [node0]
node0: stopping namenode
node2: stopping datanode
node1: stopping datanode
node3: ssh: connect to host node3 port 22: No route to host
Stopping secondary namenodes [0.0.0.0]
0.0.0.0: stopping secondarynamenode
[root@node0 .ssh]# jps
5464 Jps

参考资料 http://mashibing.com/w/